/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.nexmark.queries;



import com.bff.gaia.unified.sdk.nexmark.NexmarkConfiguration;

import com.bff.gaia.unified.sdk.nexmark.model.AuctionPrice;

import com.bff.gaia.unified.sdk.nexmark.model.Bid;

import com.bff.gaia.unified.sdk.nexmark.model.Event;

import com.bff.gaia.unified.sdk.transforms.DoFn;

import com.bff.gaia.unified.sdk.transforms.Filter;

import com.bff.gaia.unified.sdk.transforms.ParDo;

import com.bff.gaia.unified.sdk.values.PCollection;



/**

 * Query 2, 'Filtering. Find bids with specific auction ids and show their bid price. In CQL syntax:

 *

 * <pre>

 * SELECT Rstream(auction, price)

 * FROM Bid [NOW]

 * WHERE auction = 1007 OR auction = 1020 OR auction = 2001 OR auction = 2019 OR auction = 2087;

 * </pre>

 *

 * <p>As written that query will only yield a few hundred results over event streams of arbitrary

 * size. To make it more interesting we instead choose bids for every {@code auctionSkip}'th

 * auction.

 */

public class Query2 extends NexmarkQueryTransform<AuctionPrice> {

  private final int auctionSkip;



  public Query2(NexmarkConfiguration configuration) {

    super("Query2");

    this.auctionSkip = configuration.auctionSkip;

  }



  @Override

  public PCollection<AuctionPrice> expand(PCollection<Event> events) {

    return events

        // Only want the bid events.

        .apply(NexmarkQueryUtil.JUST_BIDS)



        // Select just the bids for the auctions we care about.

        .apply(Filter.by(bid -> bid.auction % this.auctionSkip == 0))



        // Project just auction id and price.

        .apply(

            name + ".Project",

            ParDo.of(

                new DoFn<Bid, AuctionPrice>() {

                  @ProcessElement

                  public void processElement(ProcessContext c) {

                    Bid bid = c.element();

                    c.output(new AuctionPrice(bid.auction, bid.price));

                  }

                }));

  }

}